How to check for linker argument support?

[Bent Bisballe Nyeng]

Hi list

I want to use the --no-undefined linker argument through the 
-Wl,--no-undefined CXXFLAGS. This is only supported by gcc but has a 
clang alternative: -Wl,-undefined,error.
I have tried writing a test in my configure.ac script to figure out 
which one should be used, but my test reports 'yes' on both gcc and 
clang, so clang never falls back to it's own variant.
My test looks like this:

dnl ===========================
dnl Check for -Wl,--no-undefined or -Wl,-undefined,error support
dnl ===========================
AC_LANG_PUSH([C++])
TMP_CXXFLAGS="$CXXFLAGS"
AC_MSG_CHECKING([whether CXX supports '-Wl,--no-undefined'])
CXXFLAGS="-Wall -Werror -Wl,--no-undefined"
AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
        [ AC_MSG_RESULT([yes])
                NO_UNDEFINED_PARAM=-Wl,--no-undefined
        ],
        [ AC_MSG_RESULT([no])
                AC_MSG_CHECKING([whether CXX supports '-Wl,-undefined,error'])
                CXXFLAGS="-Wall -Werror -Wl,-undefined,error"
                AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
                        [AC_MSG_RESULT([yes])
                                NO_UNDEFINED_PARAM=-Wl,-undefined,error
                        ],
                        [AC_MSG_RESULT([no])
                                NO_UNDEFINED_PARAM=""
                        ]
                )
        ]
)
CXXFLAGS="$TMP_CXXFLAGS"
AC_LANG_POP([C++])

Any input to what I might be doing wrong?

Kind regards
Bent Bisballe Nyeng